arm64: fix abi change caused by ILP32

hulk inclusion
category: bugfix
bugzilla: NA
CVE: NA

----------------------------

One of the ILP32 patchset rename 'compat_user_mode' and
'compat_thumb_mode' to 'a32_user_mode' and 'a32_user_mode'. But these
two macros are used in some opensource userspace application. To keep
compatibility, we redefine these two macros.

Fixes: 23b2f00 ("arm64: rename functions that reference compat term")
Signed-off-by: Xiongfeng Wang <wangxiongfeng2@huawei.com>
Reviewed-by: Hanjun Guo <guohanjun@huawei.com>
Signed-off-by: Yang Yingliang <yangyingliang@huawei.com>